The invention relates generally to medical devices to remove excess blood from congested tissue and particularly to a simple mechanical device to replace medicinal leeches.
A potential post-surgical complication of reconstructive or microvascular surgery is venous congestion. Replanted tissue may become congested due to blood clot formation in the venous outflow of the tissue, or in any situation where arterial inflow exceeds venous outflow. Furthermore, venous stasis or pooling caused by an arterial supply, which is insufficient for the reconstructed tissue can also occur following microvascular surgery. Venous congestion, if not corrected by surgery or some other means, can result in tissue death.
If surgical correction fails, the current method of treating either venous congestion or venous stasis is with live medicinal leeches. The use of leeches can present a number of problems. For example, leeches can move off congested tissue and feed on normal skin, they are difficult to use in or near orifices of the body because of their potential for migration, the quantity of blood removable by a leech is very limited, and leeches may harbor serious pathogens.
Cursory attempts have been made to develop mechanical or chemical replacements for the live medicinal leech. A simple mechanical device was used by Smoot et al. in 1995 (Smoot EC, Ruiz-Inchaustegui JA, Roth AC (1995) Mechanical Leech Therapy to Relieve Venous Congestion. J Reconstr Microsurg 11: 51-55). This device consisted of a small glass bell that was placed over a punch biopsy wound. A fluid passing through an inlet port irrigated the wound and was suctioned off via a suction port at −80 mmHg. Chemical replacements for leech therapy have also been studied. The “chemical leech” involved subcutaneous injections of calcium heparin into the reattached fingers of three patients, with drainage into dressings over the surgical site. (Barnett G. R., Taylor G.I. and Mutimer K.L. (1989). The “chemical leech:” Intra-replant subcutaneous heparin as an alternative to venous anastomosis. Report of three cases. Br J Plast Surg 42:556-558. These subcutaneous injections of anticoagulant were used to promote drainage of excess blood into the dressings of the surgical site. However, prior work has not provided an adequate clinical solution for the post-surgical complication of venous congestion. The need for the development of new techniques is clearly indicated.